Hi there. While I understand that you are concerned about the possibility of a false accusation at this stage, it's too early I think to panic or even worry about the 'what-if's' just yet.
Certainly, protect yourself by making sure you recall all the details of the the encounter; write them down and put them in a safe place. Remember this though - the vast majority of sexual encounters pass without comment, much less a false accusation, and the vast majority of false accusations don't result in a charge much less a conviction.
The advice you've received already is the best possible - learn from this for the future. Casual sexual activity with someone you barely know is unwise. You can be falsely accused by relatives, people whom you think love you, for goodness sake, so protect yourself by not taking unnecessary risks. It's the opposite side of the coin that tells women to not dress provocatively or flirt too strongly to avoid being assaulted or worse. They are horrible times we live in, but common sense suggests changes in behaviour are necessary.
'Mongolian Warriors had the courage of lions, the patience of hounds, the prudence of cranes, the long-sightedness of ravens, the wildness of wolves, the passion of fightingcocks, the keenness of cats, the fury of wild boars and the cunning of foxes.' BE A MONGOLIAN WARRIOR WHEN DEFENDING YOUR INNOCENCE!